A ground-fault circuit interrupter (GFCI) is one of the most important safety features in a modern electrical system. GFCI systems are typically connected to outlets in specific locations, particularly ones where water is present. This provides an added layer of safety beyond grounding and circuit breakers. Here is a closer look at what a GFCI outlet is and why it matters to homeowners.
What Is a GFCI Outlet?
A ground fault happens when the electricity in a line takes an unintended path. Electricians often place GFCIs in kitchens and bathrooms, for example. This is because water coming into contact with an outlet or a connected device could cause electricity to take a path into the water. If a person spills some water while filling their coffee maker, they might suffer a shock or damage the coffee maker if a ground fault happens.
A circuit interrupter is a component that turns off electricity to the outlet when it detects an issue. GFCIs constantly monitor the flow of electricity in both the hot and neutral wires. If the electricity becomes unbalanced, an indication that power is no longer returning properly to the ground, then the circuit interrupter shuts off the electric flow.
Notably, GFCIs intervene at very low levels, usually at about 4 to 6 milliamps. This is a level at which a human would perceive a noticeable shock without suffering serious harm. Also, the interrupt happens within 1/40th of a second.
Circling back to the coffee maker scenario, you would be highly unlikely to experience a dangerous shock with the circuit kicking off at 6 mA and in 1/40th of a second. A bonus is that there’s a good chance the coffee maker will also survive without damage. You should notice the circuit interruption, trace the problem to spilled water, dry the area, and then reset the circuit without much trouble. You can then resume making coffee.
Identifying a GFCI Outlet
It is important to know whether your house has GFCI outlets in appropriate locations. While GFCI outlets look a lot like standard ones, they do have two features that stand out.
The most obvious feature on all models will be a pair of buttons between the two sockets on the outlet. One will be named Test, and the other will be named Reset. The Test button allows you to verify that the circuit interrupter works by pressing it. The Reset button allows you to restore power after a test or after a circuit interruption.
LED indicators are common on all newer models and even many older ones. The newest models always display a status, with green meaning the circuit is fine and red indicating that there’s a ground fault. Many older models only display a light in the fault state, and the color isn’t consistent between models.
Circuit-Breaker GFCIs
In addition to the outlet-style GFCI, you may sometimes encounter a circuit-breaker GFCI. The big difference is that this design trips a circuit breaker in your home’s electrical panel. A circuit breaker GFCI cuts power to the entire circuit rather than a specific outlet. You might find this style of GFCI necessary if you need to protect a large appliance on the same circuit, such as a refrigerator or freezer.
However, we don’t typically recommend circuit-breaker GFCIs. First, resetting them requires resetting the breaker. Second, you may have a hard time figuring out what caused the ground fault if you have multiple GFCIs on the same circuit. Third, these models are more than twice as expensive.
National Electrical Code Requirements
The National Electrical Code (NEC) is the basis for nearly all local electrical rules in the U.S. The current NEC requires GFCI outlets within 3 feet of a sink basin’s outer edge in a bathroom and 6 feet in a kitchen. If you have a wet bar sink, the kitchen standard applies. All outdoor outlets should also have GFCI support. Garages and other accessory buildings should have GFCIs, too. If your home has an unfinished basement, the NEC requires GFCIs. Crawl spaces and utility rooms with potential moisture issues need GFCI support, also.
Renovating a home’s electrical system usually triggers a requirement that you bring the GFCI support up to code. In some regions, the law also requires GFCI upgrades before sales. Many insurers also will only insure a house if it has compliant GFCI support.
Where GFCIs Aren’t Necessary
You may have noticed by now that the common pattern for GFCI requirements tends to include proximity to water. Most homes aren’t required to have GFCIs in living rooms and bedrooms, for example. These areas don’t generally experience moisture from rain, running faucets, or humidity.
Why You Can’t Just Rely on Circuit Breakers
Some folks ask us why they can’t just rely on their home’s existing circuit breakers. The problem is that circuit breakers trip due to overloads. If you have a 40-amp circuit breaker, it isn’t going to trip until the circuit has exceeded that threshold. Lethal shocks can occur in the milliamp range so a circuit breaker simply doesn’t offer sufficient protection.
Likewise, an everyday circuit breaker isn’t meant to detect variances in the electricity’s stability. Consequently, a circuit breaker may not react at all if there’s a ground fault due to a spill near an appliance or other device.
The purpose is another factor. A circuit breaker is meant to keep your electrical system from catching fire. Conversely, a GFCI protects people and devices against shocks and electrocution.
Challenges
The biggest challenge is making sure that your home’s electrical system can support GFCI outlets. Even if your home has proper grounding and existing GFCI outlets, you should never assume that it offers sufficient support. Grounding wires can degrade, and even the grounding rod itself can corrode over time or move out of ideal contact with the ground. Our electricians will test your home’s electrical system to verify that it properly supports GFCI outlets before proceeding with a project.
GFCIs also don’t work well with appliances that sometimes suffer current losses, such as refrigerators and power tools. These devices can trigger false detections. Generally, it is best to keep these systems away from locations that call for GFCI outlets. We also strongly discourage customers from placing critical equipment, such as medical devices, in zones that require GFCI support.
Troubleshooting
GFCI outlets do not last forever, and you should know how to tell when your GFCIs have failed for good. If you’re seeing moisture or corrosion in outlet boxes, it’s time for upgrades. Recurring trips, especially when there’s no nearby wetness, are a sign of trouble. Loose sockets and wiring may require replacement, too. If you detect burnt smells, heat, or sparks from an outlet, contact our electricians immediately.
Mackey Services has been in business since 1992. We handle work for customers throughout the Houston, TX area. Our electricians are fully licensed and work on a variety of systems, including electrical panels, whole-house surge protectors, generators, and EV charging stations.
If you wish to install, upgrade or replace GFCI outlets in your Houston home, contact Mackey Services today.
